Synthetase

Tyrosyl-tRNA synthetase (YARS2) is a mitochondrial protein which catalyzes the attachment of tyrosine to tRNA(Tyr) in a two-step reaction: tyrosine is first activated by ATP to form Tyr-AMP and afterward transferred to the acceptor end of tRNA(Tyr). YARS2 gene mutations are linked with myopathy with lactic acidosis and sideroblastic anemia type 2 (MLASA2).

Tyrosyl-tRNA synthetase (YARS) is a member of the class I tRNA synthetase family. YARS is a vital enzyme which catalyzes the aminoacylation of tRNATrp with tryptophan, a critical function of the cell’s protein synthesis machinery. Expression of YARS is highly stimulated in human cells by the addition of IFN-gamma.

WARS is part of the class I tRNA synthetase family. 2 types of tryptophanyl tRNA synthetase exist, a cytoplasmic form, called WARS, and a mitochondrial form, called WARS2. WARS catalyzes the aminoacylation of tRNA(trp) with tryptophan and is induced by INF. WARS controls ERK, Akt, and eNOS activation pathways that are related with angiogenesis, cytoskeletal reorganization and shear stress-responsive gene expression.

Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. The protein encoded by this gene is a cytoplasmic enzyme which belongs to the class II family of aminoacyl-tRNA synthetases. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine into proteins. The gene is located in a head-to-head orientation with HARSL on chromosome five, where the homologous genes share a bidirectional promoter. The gene product is a frequent target of autoantibodies in the human autoimmune disease polymyositis/dermatomyositis.

Histidyl-tRNA synthetase (HARS) functions to catalyze the aminoacylation of tRNAs by their corresponding amino acids. HARS is a member of the class II family of aminoacyl-tRNA synthetases. HARS is responsible for the synthesis of histidyl-transfer RNA, which is vital for the incorporation of histidine into proteins. HARS is a frequent target of autoantibodies in the human autoimmune disease polymyositis/dermatomyositis.

Aminoacyl-tRNA synthetases are a class of enzymes that charge tRNAs with their cognate amino acids. The protein encoded by this gene is a cytoplasmic enzyme which belongs to the class II family of aminoacyl-tRNA synthetases. The enzyme is responsible for the synthesis of histidyl-transfer RNA, which is essential for the incorporation of histidine into proteins. The gene is located in a head-to-head orientation with HARSL on chromosome five, where the homologous genes share a bidirectional promoter. The gene product is a frequent target of autoantibodies in the human autoimmune disease polymyositis/dermatomyositis.

Glutathione synthetase (GSS) is the second enzyme in the glutathione biosynthesis pathway. GSS catalyses the condensation of gamma-glutamylcysteine and glycine to form glutathione. Defects in the GSS are the cause of glutathione synthetase deficiency aka GSS deficiency or 5-oxoprolinuria or pyroglutamic aciduria, which is a severe form characterized by an increased rate of hemolysis and defective function of the central nervous system.

Uridine 5'-monophosphate synthase (UMPS), is a bifunctional enzyme that catalyzes the ultimate two steps of the de novo pyrimidine biosynthetic pathway. UMPS in eukaryotes links the orotate phosphoribosyltransferase and the orotidine-5’-monophosphate (OMP) decarboxylase activities into a single protein. The harmony of these 2 enzymes is assumed to be stabilized the catalytic centers as a result of the low molar concentration of the protein in mammalian cells. Mutations in UMPS are the reason of inherited orotic aciduria disease.

Uridine 5'-monophosphate synthase (UMPS), is a bifunctional enzyme that catalyzes the ultimate two steps of the de novo pyrimidine biosynthetic pathway. UMPS in eukaryotes links the orotate phosphoribosyltransferase and the orotidine-5’-monophosphate (OMP) decarboxylase activities into a single protein. The harmony of these 2 enzymes is assumed to be stabilized the catalytic centers as a result of the low molar concentration of the protein in mammalian cells.mutations in this gene are the reason of inherited orotic aciduria disease.

Phosphoribosyl Pyrophosphate Synthetase 2, also known as PRPS2 is a member of the ribose-phosphate pyrophosphokinase family. PRPS2 catalyzes the synthesis of 5-phosphoribosyl 1-pyrophosphate from ATP and D-ribose 5-phosphate.

PRPS1 catalyzes the synthesis of phosphoribosylpyrophosphate (PRPP) that is essential for nucleotide synthesis. PRPS1 catalyzes the phosphoribosylation of ribose 5-phosphate to 5-phosphoribosyl-1-pyrophosphate, which is essential for purine metabolism and nucleotide biosynthesis. Defects in PRPS1 result in phosphoribosylpyrophosphate synthetase superactivity, Charcot-Marie-Tooth disease X-linked recessive type 5 and Arts Syndrome.

GMP synthase (GMPS) is involved in purine biosynthesis. GMPS, which is a homodimer, catalyzes the last step in the GMP synthesis pathway, specifically the ATP-dependent amination of XMP to GMP. GMPS is comprised of one GMP-binding domain and one glutamine amidotransferase type-1 domain through which it communicates its catalytic activity. GMPS is engaged in the de novo synthesis of nucleotides which are not only vital for DNA and RNA synthesis, but also supply GTP, which is involved in sevral cellular processes important for cell division. GMPS gene chromosomal translocations are linked with acute myeloid leukemias, suggesting a possible role for GMPS in carcinogenesis.

Thymidylate synthase catalyzes the methylation of deoxyuridylate to deoxythymidylate using 5,10-methylenetetrahydrofolate as a cofactor which maintains the dTMP (thymidine-5-prime monophosphate) pool vital for DNA replication and repair. Thymidylate synthase plays an important role as a cancer chemotherapeutic agent. Thymidylate synthase is the primary site of action for 5-fluoro-2-prime-deoxyuridine and several folate analogs.

GLUL catalyzes the synthesis of glutamine from glutamate and ammonia. Glutamine is a major source of energy and that takes part in cell proliferation, inhibition of apoptosis, and cell signaling. GLUL is expressed during early fetal stages, and has a role in maintaining body pH by removing ammonia from circulation. Mutations in GLUL gene are related with congenital glutamine deficiency.

GLUL catalyzes the synthesis of glutamine from glutamate and ammonia. Glutamine is a major source of energy and that takes part in cell proliferation, inhibition of apoptosis, and cell signaling. GLUL is expressed during early fetal stages, and has a role in maintaining body pH by removing ammonia from circulation. Mutations in GLUL gene are related with congenital glutamine deficiency.

GLUL catalyzes the synthesis of glutamine from glutamate and ammonia. Glutamine is a major source of energy and that takes part in cell proliferation, inhibition of apoptosis, and cell signaling. GLUL is expressed during early fetal stages, and has a role in maintaining body pH by removing ammonia from circulation. Mutations in GLUL gene are related with congenital glutamine deficiency.

Phosphopantothenate-cysteine ligase (PPCS) catalyzes the first step in the biosynthesis of coenzyme A (CoA) from pantothenic acid (vitamin B5), which is a vital universal pathway in prokaryotes and eukaryotes. PPCS, being one of the last enzymes in this pathway, converts phosphopantothenate to phosphopantothenoylcysteine.

GARS is an (alpha)2 dimer which is a member of the class II family of tRNA synthetases. GARS is a glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases which charge tRNAs with their cognate amino acids. GARS catalyzes the attachment of glycine to tRNA(Gly). In addition, GARS is able to produce diadenosine tetraphosphate (Ap4A), which is a universal pleiotropic signaling molecule required for cell regulation pathways, by direct condensation of two ATPs. GARS has been demonstrated to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis.

GARS is an (alpha)2 dimer which is a member of the class II family of tRNA synthetases. GARS is a glycyl-tRNA synthetase, one of the aminoacyl-tRNA synthetases which charge tRNAs with their cognate amino acids. GARS catalyzes the attachment of glycine to tRNA(Gly). In addition, GARS is able to produce diadenosine tetraphosphate (Ap4A), which is a universal pleiotropic signaling molecule required for cell regulation pathways, by direct condensation of two ATPs. GARS has been demonstrated to be a target of autoantibodies in the human autoimmune diseases, polymyositis or dermatomyositis.

Lysyl-tRNA synthetase (KARS) is a member of the class-II aminoacyl-tRNA synthetase family. KARS exists as both mitochondrial and cytoplasmic isoforms produced by alternative splicing, and believed to have a role in autoimmune diseases, such as polymyositis or dermatomyositis. The KARS protein functions to catalyze the aminoacylation of tRNAs by their corresponding amino acids, so linking amino acids with tRNA-contained nucleotide triplets.

Threonyl-tRNA Synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective amino acids. This 83 kDa protein is an autoantigen recognized by PL-7 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that PL-7 antibodies (similar to Jo-1 antibodies) indicate an increased risk for lung involvement, but this needs to be confirmed for a larger number of cases.

Threonyl-tRNA synthetase, cytoplasmic (TARS) is a member of the class-II aminoacyl-tRNA synthetase family. The main role of TARS is in tRNA aminoacylation. The N-terminal domain of the TARS enzyme is responsible for the competition with the ribosome whereas the catalytic and the C-terminal domain are involved in binding the 2 anticodon arm-like structures in the operator.

FARSB, also known as Phenylalanyl-TRNA Synthetase Beta is a member of the phenylalanyl-tRNA synthetase beta subunit family. FARSB is composed tetramer of two alpha and two beta subunits. In the presence of ATP, this tetramer is accountable for attaching L-phenylalanine to the terminal adenosine of the appropriate tRNA.

Phosphoribosylaminoimidazole Carboxylase (PAICS) is an enzyme involved in nucleotide biosynthesis and particularly in purine biosynthesis. PAICS is a bifunctional enzyme containing phosphoribosylaminoimidazole carboxylase activity at its N-terminal region and phosphoribosylaminoimidazole succinocarboxamide synthetase at its C-terminal region. PAICS catalyzes the conversion of 5'-phosphoribosyl-5-aminoimidazole(AIR) into 5'-phosphoribosyl-4-carboxy-5-aminoimidazole (CAIR) as described in the reaction. PAICS catalyzes steps six and seven of purine biosynthesis.

OAS1 enzyme is a member of the 2’,5’-oligoadenylate synthetase family. OAS1 is induced by interferons and uses adenosine triphosphate in 2’-specific nucleotidyl transfer reactions to synthesize 2’,5’-oligoadenylates(2-5As). These molecules in turn activate latent RNase L resulting in viral RNA degradation and the inhibition of viral replication.
OAS1 may have a role in mediating resistance to virus infection, control of cell growth, differentiation, and apoptosis. OAS1 binds double-stranded RNA and polymerizes ATP into PPP (A2'P5'A)N oligomers, which activate the latent RNase L that, once activated, cleaves single-stranded RNAs.
OAS1 gene mutations are been linked to host susceptibility to viral infection.
OSA1 gene polymorphisms are linked to the outcome of hepatitis C virus infection. Furthermore, OAS1 gene polymorphisms are linked to the susceptibility to severe acute respiratory syndrome.

The AsnRS enzyme is a member of the ligases family, specifically those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. An asparagine-tRNA ligase is an enzyme which catalyzes the chemical reaction: ATP + L-asparagine + tRNAAsn AMP + diphosphate + L-asparaginyl-tRNAAsn. The three substrates of the AsnRS enzyme are ATP, L-asparagine, and tRNA(Asn), whereas its three products are AMP, diphosphate, and L-asparaginyl-tRNA(Asn).

Aminoacyl-tRNA synthetases are a class of enzymes which charge tRNAs with their cognate amino acids. Asparaginyl-tRNA synthetase (NARS) is localized to the cytoplasm and is a member of the class II family of tRNA synthetases. The N-terminal domain characterizes the signature sequence for the eukaryotic asparaginyl-tRNA synthetases.

Aminoacyl-tRNA synthetases are a class of enzymes which charge tRNAs with their cognate amino acids. Asparaginyl-tRNA synthetase (NARS) is localized to the cytoplasm and is a member of the class II family of tRNA synthetases. The N-terminal domain characterizes the signature sequence for the eukaryotic asparaginyl-tRNA synthetases.

MTHFS is a cytosolic protein which takes part in the formate metabolic process. MTHFS along with a magnesium cofactor catalyzes the ATP-dependent reaction which reduces 5-formyltetrahydrofolate (5-MTHF) to 5,10-methenyltetrahydrofolate(MTHF). MTHF is the substrate used by MTHFR (methylenetetrahydrofolate reductase) to generate 5-MTHF. In addition, MTHF is a coenzyme used in thymidine biosynthesis by thymidylate synthase (FAD).

DARS uses a 2 step reaction to catalyze the specific attachment of an amino acid to its cognate tRNA: the amino acid (AA) is first activated by ATP to form AA-AMP and then transferred to the acceptor end of the tRNA.

Seryl-tRNA synthetase, cytoplasmic (SARS) is a member of the class-II aminoacyl-tRNA synthetase family. Aminoacyl-tRNA synthetases’ role is to catalyze the aminoacylation of tRNAs by their corresponding amino acids, as a result linking amino acids with tRNA-contained nucleotide triplets. The SARS enzyme catalyzes the attachment of serine to tRNA (Ser). SARS enzyme is probably able to aminoacylate tRNA (Sec) with serine, to form the misacylated tRNA L-seryl-tRNA (Sec), which will be then converted into selenocysteinyl-tRNA (Sec).

Acyl-CoA synthetase family member 2, also known as ACSF2 is a member of the ATP-dependent AMP-binding enzyme family. Acyl-CoA synthetases are a family of enzymes which catalyze the thioesterification of fatty acids with coenzymeA to form activated intermediates, which play a basic part in lipid metabolism as well as homeostasis of lipid-related processes. ACSF2 is required for the complex of lipid synthesis, energy production via beta-oxidation, protein acylation and fatty-acid dependent transcriptional regulation. Moreover, ACSF2 is required for fatty acid import into cells by the process of vectorial acylation.

Alanyl-tRNA synthetase is a member of the aminoacyl-tRNA synthetase family, key enzymes of protein biosynthesis which charge tRNA molecules with the respective amino acids. This 108 kDa protein is an autoantigen recognized by PL-12 antibodies which occur in a subset of patients with polymyositis and dermatomyositis. Preliminary data suggest that epitope spreading occurs in the autoimmune PL-12 response such that even antibodies to an isolated alanyl-tRNA molecule can develop.